Fast growth of the pervasive computing and handheld/communication industry has generated exploding demand for high capacity nonvolatile solid-state data storage devices. Current technology like flash memory has several drawbacks such as slow access speed, limited endurance, and the integration difficulty. Flash memory (NAND or NOR) also faces scaling problems. Also, traditional rotating storage (e.g., disc drives) faces challenges in areal density and in making components like reading/recording heads smaller and more reliable.
Resistive sense memories (RSM) are promising candidates for future nonvolatile and universal memory by storing data bits as either a high or low resistance state. One such memory, MRAM, features non-volatility, fast writing/reading speed, almost unlimited programming endurance and zero standby power. The basic component of MRAM is a magnetic tunneling junction (MTJ). MRAM switches the MTJ resistance by using a current induced magnetic field to switch the magnetization of MTJ. As the MTJ size shrinks, the switching magnetic field amplitude increases and the switching variation becomes more severe.
However, many yield-limiting factors must be overcome before resistive sense memory enters the production stage. One challenge is the magnitude of the switching current in a resistive sense memory array. In spin-torque transfer RAM (STRAM), this is dependent on several factors including characteristics of the barrier layer. Therefore, a need exists for designs that facilitate lower switching current.